1. Field of the Invention
This invention relates to a routing processing device and packet type identification device, and can for example be applied to a device which distributes the processor load related to routing processing of communication packets transmitted over a network, and to a device to identify packet types based on differences in packet formats.
2. Description of Related Art
In the past, routing processing has been applied to packets transmitted over a network.
Routing processing involves selection of the optimal route to the target destination, and delivery via this route to the target destination. Routing processing requires packet classification, filtering, forwarding, and other processing. Packet classification is the classification of communication packets by type. Filtering entails judgment of whether a communication packet is to be allowed to pass or discarded, based on the transmission and reception addresses, protocol, identifier, and similar of the communication packet. Forwarding is the sending, over an appropriate selected route, of a communication packet based on the destination address of the communication packet. These kinds of processing are normally performed in a unified manner by a single general-purpose or specialized processor.
Such technology of the prior art is for example disclosed in Japanese Patent Laid-open Nos. 2000-83055, 2000-349770, and 2002-111712.
However, although in recent years there have been dramatic improvements in the circuit transmission rates of networks, the processing speeds of processors which perform routing processing have not improved sufficiently to keep pace. Consequently a considerable load is placed on a single processor which performs unified routing processing.
In recent years, there have been demands that processors performing routing processing be provided with a device to prevent improper access (such as for example a firewall) in order to compensate the high security of networks, a network load distribution device, and other high-functionality processing capabilities. Consequently, a large load has been placed on the processors performing routing processing in order to perform processing for such advanced functionality.
Hence in the technology of the prior art, alleviation of the load of routing processing placed on processors which perform routing processing has become a major issue.
In order to resolve this problem, the present invention has as an object alleviation of the load placed on processors performing routing processing. Further, because a plurality of communication packet formats are intermixed in transmission over a network, the present invention has as an object the provision of a packet type identification device which can easily identify packet types based on packet formats, and by this means can alleviate the load placed on the processor.